These four tweeter models share the same basic design but differ as follows:TW030WA05: 4 ohm, no ferro fluidTW030WA06: 4 ohm, with ferro fluidTW030WA07: 8 ohm, no ferro fluidTW030WA08: 8 ohm, with ferro fluid.Real high-end tweeter design with extremely low resonance frequency and distortion.Thanks to the extensive internal venting between three internal cavities no air inside is trapped. This feature extends the usable frequency range downwards to an extend very rarely found on tweeters.Adding the high power handling this tweeter is the natural candidate for high-end 2-way speaker systems.

Note 1. It is generally a rough simplification to assume that loudspeaker transducer voice coils exhibit the characteristics of an inductor. Instead it is a far more accurate approach to use the more advanced model often referred to as the “Wright empirical model”, also used in LEAP-4 as the TSL model (www.linearx.com), involving parameters Krm, Erm, Kxm, and Exm. This more accurate transducer model is described in a technical paper (PDF) here.